They seem like they’d be old hell-raising pals, but Al Pacino and Keith Richards met for the first time Wednesday at HBO’s starry premiere of Pacino and David Mamet’s movie “Phil Spector.” “We have a mutual friend,” Richards was overheard telling Pacino at Time Warner Center. “Johnny Depp!” Pacino replied, “I love Johnny!” and the legends bonded. (An astute spy further pointed out that “Keef” dated Ronnie Spector in 1964, years before she married music mogul Phil. And Ronnie said just recently, “I should have married Keith.”) At an after-party at Porter House, producer Barry Levinson also had Depp on the brain: He told guests, including Regis Philbin and Joy Behar, that he’ll start directing “Black Mass,” starring Depp as Boston gangster Whitey Bulger in June. Also at the bash: David Chase, Zosia Mamet and Lou Reed. Linda Kenney Baden, Spector’s lawyer, attended — but the actress who played her in the film, Helen Mirren, was onstage in London as Queen Elizabeth II in Peter Morgan’s play “The Audience.”